Bristol's suit rules go out the window here, and reserve piles start seven cards deep. One deck, medium difficulty, and a tougher 35% win rate.

Thomas Warfield opened up Bristol Solitaire to create Castile Solitaire, swapping in fans that ignore suit and reserve piles that start with seven cards apiece. It's a medium game, with a 35% chance of winning, played with a single deck, and your result comes down mostly to skill and luck.
If you enjoy Castile, try Bristol Solitaire or original Solitaire, a classic card game.
If you run into anything odd or have an idea that would make the game better, please contact me.
Have a good time playing!
4 foundation piles: Build up from Ace to King in the same suit.
8 Fans: Build down regardless of suit. Only the top card of each pile is playable. Only Kings can fill spaces. At the start of the game, each pile is given three cards.
4 reserve piles: No particular order. Each pile's top card can be played to the foundations or fans. There are no empty spaces here. At the start of the game, each pile gets 7 cards.
There are four foundation piles.
Any ace can be placed on an empty foundation pile.
A card can be added to a foundation pile only if it's one rank higher and the same suit as the pile's current top card, so the only card that fits on a 9 of spades is a 10 of spades. Each pile holds up to 13 cards.
The top card of each foundation can be moved back into play if another pile will accept it.
There are four reserve piles, each dealt seven cards to start. Every card is dealt face-up. Nothing can be moved into the reserves. Each reserve's top card can be played to the tableau or the foundation.
Eight tableau piles of three cards each, all dealt face-up.
A card can be added to a tableau pile only if it's one rank lower than the pile's current top card, regardless of suit, so the only card that fits on a five is a four.
Cards on the tableau that are not covered by another card are free to be played onto the foundation or any other tableau pile.
Only kings may fill empty spots in the tableau.
Only one card may be moved at a time; sequences are not permitted.